Recent technological developments have made it possible to image the nyocardium via the esophagus using sonographic methods. We plan to investigate the utilization of this method and further develop it for patient monitoring. In particular, modifications will be made in esophageal probes to obtain multi-images at various angles through the heart. Three-dimensional computer reconstructions methods will then be employed for computing left-ventricular volumes at both systole and diastole from this multi-planar information. Therefore, ejection fraction, diastolic volume, and stroke volume will be derived and used to assess myocardial performance. The primary aim is toward application of this technology in the operating room in patient management, but we plan to investigate its use elsewhere as well. In order to determine the accuracy of these measurements they will be compared to other measurement modalities. Further, the clinical utility of the system in patient management will be assessed. Initially, off-line analysis will be performed using semi-manual processing methods. However, computer and other hardware processing methods will be developed as well as special probe configurations to allow measurements to be made rapidly and on-line.